<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>Document</title>
	<style type="text/css">
		*{
			margin: 0;
			padding:0;
		}
		.header{
			width: 980px;
			margin: 0 auto;
		}
		.header .logo{
			float: left;
			width: 150px;
			height: 100px;
			background-color: gold;
		}
		.header .nav{
			float: left;
			width: 400px;
			height: 40px;
			background-color: green;
			margin-left: 50px;
		}

		.content{
			width: 980px;
			margin: 0 auto;
		}
		.content .ad{
			float: left;
			width: 120px;
			height: 600px;
			background-color: gray;
		}
	</style>
</head>
<body>
	<div class="header">
		<div class="logo">logo</div>
		<div class="nav"></div>
	</div>
	
	<div class="content">
		<div class="ad">我是content里面的广告</div>
	</div>
</body>
</html>